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Why is the 741 op amp still produced?
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SilverSolder:
Wondering why it is cheaper to store them as wafers and build the ICs later, rather than just asking the original supplier to make a batch of product on the lines that have already been set up for it, before powering down for the last time...   and storing the output of that run?   Is it because you then have flexibility to put that chip into different packages etc.?
David Hess:

--- Quote from: SilverSolder on October 01, 2020, 06:59:09 pm ---I have a batch of transistors whose actual breakdown voltage is astronomical compared to the specification.   Does/did it ever happen in production, that the process improved to the point where even the lowest specced parts easily achieved the performance of the (older) highest rated parts - so the lower rated parts effectively became price/performance "bargains" (but not advertised, so nobody would ever know)?
--- End quote ---

I have seen that happen with some transistors where the lowest specified parts became unavailable, and were eventually discontinued in favor of the higher voltage parts.


--- Quote from: Kleinstein on October 01, 2020, 08:50:25 pm ---As far as I have heard most of today's TL082 OPs are also low enough in noise to meet the TL072 specs, which is the lower noise variant, otherwise identical.
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Noise tests tend to be time consuming which adds cost to production, so it is not surprising that TL072s often meet the noise specification for the TL082.  On the other hand, I have hardly ever seen any price difference when buying these parts so I buy the presumably noise tested TL082 series in favor of the TL072.


--- Quote ---A few days ago a found an article showing a lateral BJT in an standard 1.2 µm CMOS process and an OP with 2 such BJTs for the input and the rest MOSFETs. So kind of mixed MOS and BJT the other way around than in the early days. The lateral transistor were supposed to be even good quality (low noise, good gain, though slow) - not the marginal PNPs in the 741.
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A couple weeks ago I searched for examples of operational amplifiers which support a high differential input voltage range that are built on a modern process and found nothing.  I was specifically looking for modern replacements for the 741 and 301A types of operational amplifiers.  The closest ones I found are single supply 324/358 type improved parts like the LT1006/LT1013/LT1014 which obviously make use of high voltage PNPs but are hardly modern despite their high performance.
Kleinstein:
For OPs with a larger input differential the main option to look at are FET input types (e.g. OPA196/7). Even there some JFET types (e.g. OPA170-172) have a limited input differential. A moderate cost (can be comparable to 741), slightly improved lm358 is the MC33172.

The TL072 is the version with lower noise specs, the TL082 was the low cost version that allowed more noise. Chances are these are not individually tested - probably just a few per batch. I also noted essentially no price difference.

The lower grade transistors (lower gain bins or lower voltage bins) can become rarer though still in the program but less likely at the distributors. There however one exception: the higher supply variants for some OPs are not taking over. For some reasons there are still LM2904 ( = lower voltage grade of LM358) available - could be just LM358 with less testing for the penny pitchers.
tszaboo:

--- Quote from: coppice on October 02, 2020, 08:19:46 pm ---
--- Quote from: NANDBlog on October 02, 2020, 06:22:51 pm ---Well, kinda. Remember Fairchild? They had no obsolescence policy, until ON bought them. ON is obsoleting like half their portfolio as we speak.

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A blanket no obsolescence policy is ridiculous, and obviously won't be kept to. When they sell just a few hundred a year, do you really think its viable to not obsolete the part? When the fab is unmaintainable, do you really think its viable to not obsolete the part?

The first time I got to see from the inside the point at which old parts get dropped I was astonished how long that vendor had continued with supply. Many of the parts dropped on that occasion sold just a few thousand per annum, and hadn't sold in decent quantities for years. Vendors serving things like the consumer and computer markets tend to have fairly short windows of opportunity for their parts, and are dropping them all the time. Vendors serving industrial customers are at the opposite end of the scale. Large vendors, serving many markets, may have different practices in each division.


--- Quote from: NANDBlog on October 02, 2020, 06:22:51 pm ---Microchip throw out entire product lines from Atmel.
Littlefuse just throw out IXYS's solar panel portfolio
IRF was decimated by Infineon. When they bought them, it was synergy (sound of angels in  the background), after a year it was too much overlap.

--- End quote ---
I wonder how many of those parts were sold per annum? I doubt too many high volume, decent margin parts were dumped at the drop of a hat. Political infighting obviously plays a part, but its mostly down to volumes, margins, and the technology still being available to make the parts.

--- End quote ---
The no obsolescence policy was rolled out in 2013, and ON bought them in 2016, so we will never know if this would've worked. In all fairness, Fairchild had a fairly "established" portfolio, they weren't chasing trends, just making parts for industrial applications. Only a few new IC was for new applications, like SIM card switch and other low-tech parts.

IDK, how many parts Atmel or IRF was selling. I think the part which got canned was Atmels FPGA portfolio, that was very old designs. So you can imagine, anyone using those had a very good reason to use them.
Like that company, open sourcing their respirator. They used some 20 year old ST microcontoller.

The reason to keep these going is simple. They are used in the train your are taking to work. In the hospital equipment. In the nuclear powerplant controller board. Even if you only sell 100 of these parts, we need these parts.
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